Boosting performance with Mysql partitions

Boosting performance with

MySQL partitions

Giuseppe MaxiaMySQL Community Team Lead

twitter: @datacharmer

Thursday, 30 September 2010

about me -Giuseppe Maxia a.k.a. The Data Charmer MySQL Community Team Lead Long time hacking with MySQL features Formerly, database consultant, designer, coder. A passion for QA An even greater passion for open source ... and community Passionate blogger http://datacharmer.blogspot.com


http://datacharmer.blogspot.com




















Slides for this presentation

http://tinyurl.com/mysql-partitions

This work is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported License.




Table of contents

Your needs

What

Partition pruning

Benchmarking

leveraging replication

tips

hands on

tools

Syntax

Partitioning by date


Table of contents

Your needs

What

Partition pruning

Benchmarking


tips

hands on

tools

Syntax



The problem(s)• Too much data• Not enough RAM• Historical data• Growing data• Rotating data

6


Too much data

7

data


Not enough RAM

8

data

RAM

INDEXESINDEXES


Not enough RAM

9

dataRAMINDEXES

INDEXES


Table of contents

Your needs

What

Partition pruning

Benchmarking


tips

hands on

tools

Syntax



What exactly is this "partitions" thing? Logical splitting of tables Transparent to user


Remember the MERGE tables? separate tables risk of duplicates insert in each table no constraints

MERGE TABLE


It isn't a merge table! One table No risk of duplicates insert in one table constraints enforced

PARTITIONED TABLE


Wait a minute ...• WHAT THE HELL DOES "LOGICAL SPLIT" REALLY

MEANS?• LET ME EXPLAIN ...

14


Physical partitioning (1)• Take a map

15


Physical partitioning (2)• cut it into pieces

16


Physical partitioning (3)• What you have, is several different pieces

17


Physical partitioning (4)• If you want the map back, you need some application

(adhesive tape) and you may get it wrong

18


Logical partitioning (1)• Take a map

19


Logical partitioning (2)• fold it to show the piece you need

20


Logical partitioning (3)• what you have is still a map, even if you see only one

part.

21


Logical partitioning (4)• if you unfold the map, you still have the whole thing

22


Table of contents

Your needs

What

Partition pruning

Benchmarking


tips

hands on

tools

Syntax



Partition pruning 1a - unpartitioned table - SINGLE RECORD

select * from table_name where colx = 120


Partition pruning 1a - unpartitioned table - SINGLE RECORD


INDEX

DATA


Partition pruning 1b - unpartitioned table - SINGLE RECORD



Partition pruning 1c - unpartitioned table - RANGE

select * from table_name where colx between 120 and 230


Partition pruning 2a - table partitioned by colx - SINGLE REC


100-199

1-99

200-299

300-399

400-499

500-599


Partition pruning 2a - table partitioned by colx - SINGLE REC


DATA I

NDEX

100-199

1-99

200-299

300-399

400-499

500-599


Partition pruning 2b - table partitioned by colx - SINGLE REC


100-199

1-99

200-299

300-399

400-499

500-599


Partition pruning 2c - table partitioned by colx - RANGE

100-199

1-99

200-299

300-399

400-499

500-599

select * from table_name where colx between 120 and 230


Partition pruning

EXPLAINselect * from table_name where colx = 120

EXPLAIN PARTITIONSselect * from table_name where colx = 120

in 5.1

before


Partition pruning - unpartitioned tableexplain partitions select count(*) from table_name where colx=120\G***** 1. row **** id: 1 select_type: SIMPLE table: table_name partitions: NULL type: index...


Partition pruning - unpartitioned tableexplain partitions select count(*) from table_name where colx between 120 and 230\G***** 1. row **** id: 1 select_type: SIMPLE table: table_name partitions: NULL type: index...


Partition pruning - table partitioned by colxexplain partitions select count(*) from table_name where colx between 120 and 230\G***** 1. row **** id: 1 select_type: SIMPLE table: table_name partitions: p02,p03 type: index...


Table of contents

Your needs

What

Partition pruning

Benchmarking


tips

hands on

tools

Syntax



Partitioning Types Partition a table using CREATE TABLE or ALTER TABLE

CREATE TABLE <table_name> (<columns>) ENGINE=<engine_name> PARTITION BY <type> ( <partition_expression> );

<type> can be RANGE LIST HASH KEY


RANGECREATE TABLE Employee ( emp_id INT AUTO_INCREMENT, name VARCHAR(50), store_id TINYINT, PRIMARY KEY (emp_id)) ENGINE=MyISAMPARTITION BY RANGE (emp_id) ( PARTITION p0 VALUES LESS THAN (10000), PARTITION p1 VALUES LESS THAN (20000), PARTITION p2 VALUES LESS THAN (30000), PARTITION p3 VALUES LESS THAN (40000), PARTITION p4 VALUES LESS THAN MAXVALUE)

• MAXVALUE is optional• Partition ranges must be listed smallest to greatest

and must be integersThursday, 30 September 2010

Table of contents

Your needs

What

Partition pruning

Benchmarking


tips

hands on

tools

Syntax



Benchmarking partitions Compare results Unpartitioned vs partitioned ISOLATION Repeatability Check your resources!


Benchmarking partitions - Compare results Execute query Record execution time CHECK RETRIEVED RECORDS!


Benchmarking partitions - Unpartitioned vs partitioned Make it simple. Do not change structure If needed, remove PK from partitioned table


Benchmarking partitions - ISOLATION Try to reproduce working conditions No other servers running while benchmarking Restart the server before each test Do NOT mix partitioned and unpartitioned tables in

the same server Use MySQL Sandbox


Benchmarking partitions - Repeatability Measure more than once Make sure you have the same conditions Make sure your results are consistent between runs


Benchmarking partitions - Check resources InnoDB

check disk space (uses more than MyISAM) check CPU usage

Partitioned MyISAM tables use 2 file handles per partition If you use more than one partitioned table, count

total file handles If you use Archive partitioned tables

check CPU usage check memory usage


Table of contents

Your needs

What

Partition pruning

Benchmarking


tips

hands on

tools

Syntax



Partitioning by date - limits of partitioning

Can partition only by INTEGER columns

OR you can partition by an expression, which must return an integer


Partitioning by date - your (GOOD) options GOOD ideas

YEAR(date_column) TO_DAYS(date_column)

WHY? Both functions optimized for partitions Partition pruning does not kick with other functions


Partitioning by date - HOW TO - YEARCREATE TABLE t1 ( d date)PARTITION BY RANGE (YEAR(d))(PARTITION p01 VALUES LESS THAN (1999),PARTITION p02 VALUES LESS THAN (2000),PARTITION p03 VALUES LESS THAN (2001),PARTITION p04 VALUES LESS THAN (MAXVALUE));


Partitioning by date - HOW TO - TO_DAYSCREATE TABLE t1 ( d date)PARTITION BY RANGE (TO_DAYS(d))(PARTITION p01 VALUES LESS THAN (TO_DAYS('2008-01-01')),PARTITION p02 VALUES LESS THAN (TO_DAYS('2008-02-01')),PARTITION p03 VALUES LESS THAN (TO_DAYS('2008-03-01')),PARTITION p04 VALUES LESS THAN (MAXVALUE));


Partitioning by date - How TO How it works

partition BY FUNCTION query BY COLUMN


Partitioning by date - WRONG!!!PARTITION BY RANGE(year(from_date))

select count(*) from salaries where year(from_date) = 1998;+----------+| count(*) |+----------+| 247489 | +----------+1 row in set (2.25 sec)


Partitioning by date - RIGHT

PARTITION BY RANGE(year(from_date))

select count(*) from salaries where from_date between '1998-01-01' and '1998-12-31';+----------+| count(*) |+----------+| 247489 | +----------+1 row in set (0.46 sec)


Partitioning by date - EXPLAINexplain partitions select count(*) from salaries where year(from_date) = 1998\G***** 1. row **** id: 1 select_type: SIMPLE table: salaries partitions: p01,p02,p03,p04,p05,p06,p07,p08,p09,p10,p11,p12,p13,p14,p15,p16,p17,p18,p19 type: index...


Partitioning by date - EXPLAINexplain partitions select count(*) from salaries where from_date between '1998-01-01' and '1998-12-31'\G***** 1. row **** id: 1 select_type: SIMPLE table: salaries partitions: p14,p15...


Partitioning by date with different sizes Mixing partitions by year, month, day in the same

table

HOW TO: Use the "TO_DAYS" function set appropriate intervals


Partitioning by date with different sizesALTER TABLE salaries

partition by range (to_days(from_date))

(

# 5 years

partition p01 values less than (to_days('1985-01-01')),


# 1 year








Partitioning by date with different sizesALTER TABLE salaries partition by range (to_days(from_date))(# 1 month partition p17 values less than (to_days('2001-01-01')), partition p18 values less than (to_days('2001-02-01')), partition p19 values less than (to_days('2001-03-01')), partition p20 values less than (to_days('2001-04-01')), partition p21 values less than (to_days('2001-05-01')), partition p22 values less than (to_days('2001-06-01')), partition p23 values less than (to_days('2001-07-01')), partition p24 values less than (to_days('2001-08-01')), partition p25 values less than (to_days('2001-09-01')), partition p26 values less than (to_days('2001-10-01')), partition p27 values less than (to_days('2001-11-01')), partition p28 values less than (to_days('2001-12-01')),


Table of contents

Your needs

What

Partition pruning

Benchmarking


tips

hands on

tools

Syntax



Hands on - Partitioning with MyISAM Primary key matters - not always needed Size of indexes matters


employees test database


How many partitionsfrom information_schema.partitions +-------+-----------------+----------+| pname | expr | descr | +-------+-----------------+----------+| p01 | year(from_date) | 1985 | | p02 | year(from_date) | 1986 |

... | p13 | year(from_date) | 1997 | | p14 | year(from_date) | 1998 | | p15 | year(from_date) | 1999 | | p16 | year(from_date) | 2000 | ...| p19 | year(from_date) | MAXVALUE | +-------+-----------------+----------+


How many recordsselect count(*) from salaries; +----------+ | count(*) | +----------+ | 2844047 | +----------+


How many records in 1998 not partitionedselect count(*) from salaries where from_date between '1998-01-01' and '1998-12-31';+----------+| count(*) |+----------+| 247489 | +----------+1 row in set (1.52 sec)

# NOT PARTITIONED


How many records in 1998 partitionedselect count(*) from salaries where from_date between '1998-01-01' and '1998-12-31';+----------+| count(*) |+----------+| 247489 | +----------+1 row in set (0.41 sec)

# partition p15


Deleting records in 1998 NOT partitioned

delete from salaries where from_date between '1998-01-01' and '1998-12-31';Query OK, 247489 rows affected (19.13 sec)

# NOT PARTITIONED


Deleting records in 1998 partitioned

alter table salaries drop partition p15;Query OK, 0 rows affected (1.35 sec)


Partitions with InnoDB Slower than MyISAM But more robust Requires more storage


Partitioning with InnoDB - File per table

CREATE TABLE table_name ( ... ...

) ENGINE = INNODBROW_FORMAT=COMPRESSED KEY_BLOCK_SIZE=8PARTITION BY XXXX


Partitions with InnoDB (laptop) Key points: Takes much more storage than other engines

engine storage (MB)

innodb 221myisam 181archive 74innodb partitioned (whole) 289innodb partitioned (file per table) 290myisam partitioned 182archive partitioned 72


Benchmarking results (laptop)engine query year

2000query year 2002

InnoDB 1.25 1.25

MyISAM 1.72 1.73

Archive 2.47 2.45

InnoDB partitioned whole

0.24 0.10

InnoDB Partitioned (file per table)

0.45 0.10

MyISAM partitioned 0.18 0.12

Archive partitioned 0.22 0.12


Partitions with InnoDB (huge server) Key points: Takes much more storage than other engines

engine storage (GB)

innodb (with PK) 330myisam (with PK) 141archive 13innodb partitioned (no PK) 237myisam partitioned (no PK) 107archive partitioned 13


Benchmarking results (huge server)engine 6 month rangeInnoDB 4 min 30sMyISAM 25.03sArchive 22 min 25sInnoDB partitioned by month 13.19MyISAM partitioned by year 6.31MyISAM partitioned by month 4.45Archive partitioned by year 16.67Archive partitioned by month 8.97


Partitions with Archive Key points: REMOVE INDEXES (not supported by archive) For pure statistics applications, ARCHIVE can be

ALMOST AS FAST AS MyISAM!


Partitions with ARCHIVE - in practiceCREATE TABLE titles ( emp_no INT NOT NULL, title VARCHAR(50) NOT NULL, from_date DATE NOT NULL, to_date DATE, KEY (emp_no), FOREIGN KEY (emp_no) REFERENCES employees (emp_no) ON DELETE CASCADE, PRIMARY KEY (emp_no,title, from_date))ENGINE = InnoDB;


Partitions with ARCHIVE - in practiceCREATE TABLE titles ( emp_no INT NOT NULL, title VARCHAR(50) NOT NULL, from_date DATE NOT NULL, to_date DATE #, # KEY (emp_nono), # FOREIGN KEY (emp_no) # REFERENCES employees # (emp_no) ON DELETE CASCADE, # PRIMARY KEY (emp_no,title, # from_date)) ENGINE = ARCHIVE;


Table of contents

Your needs

What

Partition pruning

Benchmarking


tips

hands on

tools

Syntax



TOOLS The INFORMATION_SCHEMA.PARTITIONS table The partition helper

http://datacharmer.blogspot.com/2008/12/partition-helper-improving-usability.html

A Perl script that creates partitioning statements The mysqldump_partition_backup






INFORMATION SCHEMA PARTITIONS table| TABLE_NAME |

| PARTITION_NAME |

| SUBPARTITION_NAME |

| PARTITION_ORDINAL_POSITION |

| SUBPARTITION_ORDINAL_POSITION |

| PARTITION_METHOD |

| SUBPARTITION_METHOD |

| PARTITION_EXPRESSION |

| SUBPARTITION_EXPRESSION |

| PARTITION_DESCRIPTION |

| TABLE_ROWS |

| PARTITION_COMMENT |


INFORMATION SCHEMA PARTITIONS tableselect * from partitions where table_name='salaries' and table_schema='employees' limit 1\G

TABLE_SCHEMA: employees

TABLE_NAME: salaries

PARTITION_NAME: p01

SUBPARTITION_NAME: NULL

PARTITION_ORDINAL_POSITION: 1

SUBPARTITION_ORDINAL_POSITION: NULL

PARTITION_METHOD: RANGE COLUMNS

SUBPARTITION_METHOD: NULL

PARTITION_EXPRESSION: from_date

SUBPARTITION_EXPRESSION: NULL

PARTITION_DESCRIPTION: '1985-12-31'

TABLE_ROWS: 18238


INFORMATION SCHEMA PARTITIONS tableselect partition_name,partition_description, table_rows from partitions where table_name='salaries' and table_schema='employees';+----------------+-----------------------+------------+| partition_name | partition_description | table_rows |+----------------+-----------------------+------------+| p01 | '1985-12-31' | 18238 || p02 | '1986-12-31' | 37915 || p03 | '1987-12-31' | 57395 || p04 | '1988-12-31' | 76840 || p05 | '1989-12-31' | 95890 || p06 | '1990-12-31' | 114520 || p07 | '1991-12-31' | 132578 || p08 | '1992-12-31' | 151019 || p09 | '1993-12-31' | 168103 || p10 | '1994-12-31' | 185121 || p11 | '1995-12-31' | 201576 || p12 | '1996-12-31' | 218244 || p13 | '1997-12-31' | 233144 || p14 | '1998-12-31' | 247458 |


The Partition helper Introduction, syntax, and examples http://forge.mysql.com/tools/tool.php?id=173


http://forge.mysql.com/tools/tool.php?id=173


The partition helper$ partition_helper --help The Partition Helper, version 1.0.1 This program creates a ALTER TABLE statement to add or reorganize partitions for MySQL 5.1 or later (C) 2008 Giuseppe Maxiasyntax: partitions_helper [options] -t --table = name -c --column = name -i --interval = name "year", "month", or a number -p --partitions = number

...


The partition helper... --first_partition = number --reorganize = name -s --start = name -e --end = name -f --function = name -l --list --prefix = name --explain


The partition helper examplepartitions_helper --table=t1 \ --column=mydate \ --interval=year \ --start=1998-01-01 --end=2002-12-01# partitions: 5ALTER TABLE t1 PARTITION by range (to_days(mydate))( partition p001 VALUES LESS THAN (to_days('1998-01-01')), partition p002 VALUES LESS THAN (to_days('1999-01-01')), partition p003 VALUES LESS THAN (to_days('2000-01-01')), partition p004 VALUES LESS THAN (to_days('2001-01-01')), partition p005 VALUES LESS THAN (to_days('2002-01-01')));


The partition helper examplepartitions_helper --table=t1 \ --column=mydate \ --interval=month \ --start=1998-01-01 --end=2002-12-01# partitions: 60ALTER TABLE t1 PARTITION by range (to_days(mydate))( partition p001 VALUES LESS THAN (to_days('1998-01-01')), partition p002 VALUES LESS THAN (to_days('1998-02-01')), partition p003 VALUES LESS THAN (to_days('1998-03-01'))

#[...] , partition p058 VALUES LESS THAN (to_days('2002-10-01')), partition p059 VALUES LESS THAN (to_days('2002-11-01')), partition p060 VALUES LESS THAN (to_days('2002-12-01')));


The partition helper examplepartitions_helper --table=t1 \ --column=mydate \ --interval=week \ --start=1998-01-01 --end=2002-12-01# partitions: 255ALTER TABLE t1 PARTITION by range (to_days(mydate))( partition p001 VALUES LESS THAN (to_days('1998-01-01')), partition p002 VALUES LESS THAN (to_days('1998-01-08')), partition p003 VALUES LESS THAN (to_days('1998-01-15'))

#[...] , partition p253 VALUES LESS THAN (to_days('2002-10-31')), partition p254 VALUES LESS THAN (to_days('2002-11-07')), partition p255 VALUES LESS THAN (to_days('2002-11-14')));


The partition helper examplepartitions_helper --table=t1 \ --column=mynum \ --interval=250 \ --start=1000 --end=3000# partitions: 8ALTER TABLE t1 PARTITION by range (mydate)( partition p001 VALUES LESS THAN (1250), partition p002 VALUES LESS THAN (1500), partition p003 VALUES LESS THAN (1750), partition p004 VALUES LESS THAN (2000), partition p005 VALUES LESS THAN (2250), partition p006 VALUES LESS THAN (2500), partition p007 VALUES LESS THAN (2750), partition p008 VALUES LESS THAN (3000));


Partitions maintenance through events An article by Greg Haase about this topic http://dev.mysql.com/tech-resources/articles/

partitioning-event_scheduler.html


http://dev.mysql.com/tech-resources/articles/partitioning-event_scheduler.html




mysqldump_partition_backup a script created by Roland Bouman http://forge.mysql.com/tools/tool.php?id=258 detects the partitions for a table, and generates

mysqldump statements for each one




Table of contents

Your needs

What

Partition pruning

Benchmarking


tips

hands on

tools

Syntax



the NULL partition• when partitioning by date• using TO_DAYS• the first partition matters

92

partition rowsp1 100,000p2 150,000p3 120,000p4 100,000


partition condition rows

p1 to_days('1990-01-01') 1,000,000

p2 to_days('1990-02-01') 1,000,000

p3 to_days('1990-03-01') 1,000,000

p4 to_days('1990-04-01') 1,000,000

p5 to_days('1990-05-01') 1,000,000

p6 to_days('1990-06-01') 1,000,000


partition condition rows

p1 to_days('1990-01-01') 1,000,000

p2 to_days('1990-02-01') 1,000,000

p3 to_days('1990-03-01') 1,000,000

p4 to_days('1990-04-01') 1,000,000

p5 to_days('1990-05-01') 1,000,000

p6 to_days('1990-06-01') 1,000,000

date_field between '1990-04-10' and '1990-04-15'

= 2,000,000 rows


partition condition rowsp0 0 0p1 to_days('1990-01-01') 1,000,000p2 to_days('1990-02-01') 1,000,000p3 to_days('1990-03-01') 1,000,000p4 to_days('1990-04-01') 1,000,000p5 to_days('1990-05-01') 1,000,000p6 to_days('1990-06-01') 1,000,000

alter table t1 reorganize partition p1 into ( partition p0 values less than (0), partition p1 values less than (to_days('1990-01-01')));


partition condition rowsp0 0 0p1 to_days('1990-01-01') 1,000,000p2 to_days('1990-02-01') 1,000,000p3 to_days('1990-03-01') 1,000,000p4 to_days('1990-04-01') 1,000,000p5 to_days('1990-05-01') 1,000,000p6 to_days('1990-06-01') 1,000,000

date_field between '1990-04-10' and '1990-04-15'

= 1,000,000 rows


Lock before inserting single records• If you send MANY SINGLE INSERT at once• LOCK before inserting

• No need to do it for bulk inserts

97


Table of contents

Your needs

What

Partition pruning

Benchmarking


tips

hands on

tools

Syntax



Replication schemes

99

SLAVESLAVE

MASTER

INNODBNOTPARTITIONED

INNODBPARTITIONEDBY RANGE

MyISAMPARTITIONEDBY RANGE

concurrent insert

concurrent batch processing large batch processing

SLAVE

INNODBNOTPARTITIONED

concurrent read


Replication schemes

100

SLAVESLAVE

MASTER

INNODBPARTITIONED BY HASH

MyISAMPARTITIONED BY RANGE

INNODBNONPARTITIONED

concurrent insert

concurrent readsbatch processingThursday, 30 September 2010

Replication schemes - dimensions

101

MASTER

INNODBPARTITIONED BY HASH

ARCHIVEPARTITIONEDBY RANGE (date)

ARCHIVEPARTITIONEDBY RANGE (product)

concurrent insert

dimensional processing dimensional processing

SLAVE

ARCHIVEPARTITIONEDBY RANGE (locations)

dimensional processing

SLAVESLAVE


Slides for this presentation


This work is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported License.




THANKS!

Q&AComment on Twitter: @datacharmer


BONUS SLIDES

NEWFEATURES

104


MySQL 5.5 enhancements• PARTITION BY RANGE COLUMNS• PARTITION BY LIST COLUMNS• TO_SECONDS

105


MySQL 5.5 enhancements

106

CREATE TABLE t ( dt date)PARTITION BY RANGE (TO_DAYS(dt))( PARTITION p01 VALUES LESS THAN (TO_DAYS('2007-01-01')), PARTITION p02 VALUES LESS THAN (TO_DAYS('2008-01-01')), PARTITION p03 VALUES LESS THAN (TO_DAYS('2009-01-01')), PARTITION p04 VALUES LESS THAN (MAXVALUE));

BEFORE

5.1



107

SHOW CREATE TABLE t \G Table: tCreate Table: CREATE TABLE `t` ( `dt` date DEFAULT NULL) ENGINE=MyISAM DEFAULT CHARSET=latin1/*!50100 PARTITION BY RANGE (TO_DAYS(dt))(PARTITION p01 VALUES LESS THAN (733042) ENGINE = MyISAM,[…]

BEFORE

5.1



108

CREATE TABLE t ( dt date)PARTITION BY RANGE COLUMNS (dt)( PARTITION p01 VALUES LESS THAN ('2007-01-01'), PARTITION p02 VALUES LESS THAN ('2008-01-01'), PARTITION p03 VALUES LESS THAN ('2009-01-01'), PARTITION p04 VALUES LESS THAN (MAXVALUE));

AFTER5.5



109

SHOW CREATE TABLE t Table: tCreate Table: CREATE TABLE `t` ( `dt` date DEFAULT NULL) ENGINE=MyISAM DEFAULT CHARSET=latin1/*!50500 PARTITION BY RANGE COLUMNS(dt)(PARTITION p01 VALUES LESS THAN ('2007-01-01') ENGINE = MyISAM,[…]

AFTER5.5


MySQL 5.5 - Multiple columns

110

CREATE TABLE t ( a int, b int)PARTITION BY RANGE COLUMNS (a,b)( PARTITION p01 VALUES LESS THAN (10,1), PARTITION p02 VALUES LESS THAN (10,10), PARTITION p03 VALUES LESS THAN (10,20), PARTITION p04 VALUES LESS THAN (MAXVALUE, MAXVALUE));


partition definitionpartition definitionpartition definitionby range (a,b)by range (a,b)by range (a,b)

partition LESS THANLESS THANp01 10 10p02 10 20p03 10 30p04 10 MAXVALUEp05 MAXVALUE MAXVALUE

recordsrecordsa b1 10

10 910 1010 11




(1,10) < (10,10) ?

(a < 10)OR

((a = 10) AND (b < 10))

(1 < 10)OR

((1 = 10) AND (10 < 10)) TRUE


10 910 1010 11




(10,9) < (10,10) ?

(a < 10)OR

((a = 10) AND (b < 10))

(10 < 10)OR

((10 = 10) AND (9 < 10)) TRUE


10 910 1010 11




(10,10) < (10,10) ?

(a < 10)OR

((a = 10) AND (b < 10))

(10 < 10)OR

((10 = 10) AND (10 < 10)) FALSE


10 910 1010 11




(10,10) < (10,20) ?

(a < 10)OR

((a = 10) AND (b < 20))

(10 < 10)OR

((10 = 10) AND (10 < 20)) TRUE


10 910 1010 11


116

CREATE TABLE employees ( emp_no int(11) NOT NULL, birth_date date NOT NULL, first_name varchar(14) NOT NULL, last_name varchar(16) NOT NULL, gender char(1) DEFAULT NULL, hire_date date NOT NULL) ENGINE=MyISAMPARTITION BY RANGE COLUMNS(gender,hire_date)(PARTITION p01 VALUES LESS THAN ('F','1990-01-01'), PARTITION p02 VALUES LESS THAN ('F','2000-01-01'), PARTITION p03 VALUES LESS THAN ('F',MAXVALUE), PARTITION p04 VALUES LESS THAN ('M','1990-01-01'), PARTITION p05 VALUES LESS THAN ('M','2000-01-01'), PARTITION p06 VALUES LESS THAN ('M',MAXVALUE), PARTITION p07 VALUES LESS THAN (MAXVALUE,MAXVALUE)


MySQL 5.5 enhancements• TRUNCATE PARTITION• TO_SECONDS()

117


MySQL 5.6 enhancements• ALTER TABLE … EXCHANGE PARTITION

118


ALTER TABLE t1EXCHANGE PARTITION p2WITH TABLE t2


9 i www

10 j xxx

11 k yyy

12 l zzz

5 e zzz

6 f www

7 g ccc

8 h sss

f1 f2 f3

1 a xxx

2 b xxx

3 c yyy

4 d xxx

p1

p2

p3

f1 f2 f3

(empty)(empty)(empty)

t1 t2


9 i www

10 j xxx

11 k yyy

12 l zzz

5 e zzz

6 f www

7 g ccc

8 h sss

f1 f2 f3

1 a xxx

2 b xxx

3 c yyy

4 d xxx

p1

p2

p3

f1 f2 f3

(empty)(empty)(empty)

t1

t2


9 i www

10 j xxx

11 k yyy

12 l zzz

(empty)

f1 f2 f3

1 a xxx

2 b xxx

3 c yyy

4 d xxx

p1

p2

p3

t1 t2

f1 f2 f3

5 e zzz

6 f www

7 g ccc

8 h sss


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Boosting performance with Mysql partitions

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